The invention relates to air cooling and cleaning apparatus for use in connection with the development of a compressed-air supply for operating air brakes on automotive equipment or for use in many industrial applications, as, for instance, compressed-air operated tools, valves and instruments, and other compressed-air operated or controlled equipment.
The compression of the air, by means of an air compressor, to a pressure in the customary range [of 80 to 150 pounds per square inch (5.63 to 10.56 kilograms per square centimeter) or more] raises the temperature of the air by several hundred degrees, as, for instance, 300.degree. F. (148.degree. C.), more or less, depending on the pressure. For efficient storage and use, the temperature of the compressed air must be reduced as near ambient temperature as possible. The compressed air, as it leaves the compressor, may also have entrained therein some of the lubricant oil used to lubricate the compressor or an air whipped or aerated and perhaps somewhat aqueous emulsion-like form of such oil, and may also have entrained therein dust and other solid contaminants such as carbon particles resulting from the carbonization of lubricant oil. Another contaminant and frequently the largest contaminant is the moisture drawn into the compressor along with the atmospheric air. The extent of this contaminant varies of course with the degree of humidity. However, whatever the humidity, moisture and water entrained in the compressed-air leaving the compressor represents a hazard in the operation of air brakes and other equipment to be operated or controlled by the compressed air.
The object of the present invention is the efficient and reliable cooling of the compressed-air and the removal therefrom of its moisture or water content and the removal therefrom of the oil (or emulsion) discharged by the compressor and dust and carbon particles and other contaminants entrained therein, while the compressed air flows from the compressor to the storage reservoir. A further object is a construction in air coolers and cleaners which is durable, trouble free and economical to manufacture.
The compressed-air cooler and cleaner disclosed herein is preferably formed, in the main, of a material, such as aluminum or an aluminum alloy, having a high thermal conductivity and high tensile strength, and it includes a generally upright cylindrical tubular body or housing formed of thick-walled tubing extruded out of such aluminum or aluminum alloy. A funnel-like member, whose flange is of a diameter neatly fitting into the inner diameter of the tubular housing, divides the tubular housing into a relatively short lower swirl chamber or spin chamber and a relatively longer (or higher) upper cooling chamber, with the tube of the funnel extending down deep into the swirl chamber. A drain opening is provided at or near the bottom of the swirl chamber, to which opening an automatic pilot-air controlled drain valve is connected. A compressed air inlet communicates with the upper portion of the swirl chamber and is arranged to deliver the incoming compressed air tangentially of the swirl chamber. An upper housing closure or lid is secured to the upper end of the tubular housing, in fluid sealed relation thereto, and has an air delivery or exit opening extending therethrough. A hollow cylindrical non-metallic air director of low thermal conductivity, having its upper end closed and its lower end open, is operatively and co-axially disposed within the cooling chamber, with the outer surface thereof spaced a short distance radially inwardly from the inner surface of the cooling chamber, so as to form a narrow vertical air passageway of annulus shaped cross section between the inner surface of the cooling chamber and the outer surface of the air director. A filter chamber or filter housing is carried by and extends downwardly from the upper housing closure and is preferably formed integrally therewith, and has an inwardly extending filer-supporting flange at the lower end thereof.
The tubular housing has a uniform interior diameter throughout its length. The flange of the funnel is supported horizontally on the heads of three equidistantly spaced rivets whose stems extend through and suitably beyond and are fluid tight in corresponding holes through the wall of the tubular housing, and the outer ends of the stems are riveted over on the outside, against the outer surface of the tubular housing.
The lower open end of the air director is supported on a stepped-diametered perforated disc whose upper small-diametered portion is snugly telescoped into the lower end of the air director, and such disc is in turn supported by the flange of the funnel through three or four equidistant short vertical spacer members. The air director supporting disc has three or four equidistantly spaced laterally extending centering projections which extend out to the inner surface of the wall of the tubular housing and thus space the lower end of the air director uniformly in relation to such inner surface of the housing. The upper closed end of the air-director is similarly spaced from the inner surface of the wall of the housing, in coaxial relation thereto, by lateral projections extending outwardly from the upper closure or lid thereof. The short vertical spacers which space the air director a short distance above the flange or the funnel may be either spacers formed integrally with and extending downwardly from the stepped-diametered director-supporting disc, with their lower ends resting on the flange of the funnel, or such spacers may be short vertical spacers riveted or spot welded or otherwise secured to the flange of the funnel, with their upper ends supporting the director-supporting disc.
A spring intermediate the filter housing and the upper closed end of the air director (or between the upper housing-closure and the upper closed end of the air-director) serves resiliently to press the air director downwardly and to press the air director supporting disc against the aforementioned vertical spacers therebeneath and so to press the funnel flange against its supporting rivet heads, so that the space between the lower end of the air director (or between the lower face of its supporting disc) and the flange of the funnel is no more than the height of the aforementioned vertical spacers, and yet so that the air director can be raised upwardly to a slight extent against the force of said spring if the free passage of the compressed air requires the raising of the air director. The filter within the filter housing is pressed downwardly against a lower annular filter supporting flange of the filter housing by means of a spring between the filter and the upper housing closure so that if the filter becomes unduly clogged the compressed air will lift the filter from said supporting flange to permit the compressed air to bypass the filter.
Generally rectangular sheet aluminum cooling fins, having central openings for telescopically receiving the tubular housing and having short cylindrical flanges at their inner diameters, are press fitted and/or heat shrunk onto the outside of the tubular housing, with the flanges thereof in firm thermally-conductive contact with the outer surface of the tubular housing and spacing the fins from one another.
The compressed air entering the swirl chamber tangentially near the top thereof, rapidly spins or swirls downwardly, thereby imposing a centripetal force upon the compressed air in the swirl chamber and upon any solid or liquid particles entrained in the compressed air. The swirling air exits upwardly from the swirl-chamber through the downwardly extending tube of the funnel and enters the cooling chamber beneath the air director therein. The air in the space between the lower end of the tube of the funnel and the bottom of the swirl chamber continues to swirl or spin. The spinning or swirling of the air both above and below the lower end of the tube of the swirl chamber separates out most of the water, oil and solid particles (entrained in the compressed air) before the compressed air rises upwardly through the funnel tube for passage between the air director and the inner wall surface of the cooling chamber. The solid particles and oil droplets and condensed moisture in the form of water droplets which have been so centripetally separated from the swirling compressed air drop to the bottom of the swirl chamber and are periodically flushed therefrom through the drain opening at the bottom of the swirl chamber by means of the automatic drain valve connected thereto.
Such moisture as is not condensed and separated from the compressed air in the swirl chamber is condensed by the contact of the air with the inner wall surface of the tubular housing and drains down therealong onto the disc of the funnel and then down into the tube of the funnel and into the swirl chamber and then drops to the bottom of the swirl chamber.
Such air-entrained particles as are not separated from the air in the swirl chamber are filtered out by the filter which is just beneath the upper housing closure.